Objective The effects of Womersley number and Reynolds on the wall shear stress and wall pressure are discussed. Then the effects of flow patterns on the endothelium and the elasticity of the vascular wall are analyzed. Methods Two-dimensional symmetrical models are used to simulate the unsteady flow in the AAA models. Results Mean Reynolds number and Womersley number that affect the flow pattern and wall shear stress and wall pressure in the aneurysm are dealt with. The mean Reynolds number and Womersley number increase the strength of the vortex in the AAA. Conclusion This rapid oscillating nature of the shear stresses and wall pressure over a long period of time may be directly correlated with endothelial biology and atherogenesis and could have some weakening effects on the strength of the artery wall. These should have facilitated the initiation, growth and rupture of the aneurysm to some extent.